<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style>
        *{
            margin: 0;
            padding: 0;
        }

        .a1,.a2,.a3{
            width: 400px;
            height: 100px;
        }

        .a1{
            background-color: red;
            z-index: 3;
            animation: a 1s 0s both;
        }

        .a2{
            background-color: black;
            z-index: 2;
            animation: a 1s  0.3s   both;
        }

        .a3{
            background-color: brown;
            z-index: 1;
            animation: a 1s 0.6s both;
        }

        @keyframes a{
            0%{
                opacity: 0;
                transform: translateY(100%);
            }
            
            100%{
               opacity: 1;
            transform: translateY(0%);
            }
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="a1">

        </div>
        <div class="a2">

        </div>
        <div class="a3">

        </div>
    </div>
</body>
</html>